Hydraulic system and remotely operated flow control arrangement therein



J, D. ALLEN 3,381,936 HYDRAULIC SYSTEM AND REMOTELY OPERATED FLOW May 7, 1968 CONTROL ARRANGEMENT THEREIN Filed Feb.

United States Patent O HYDRAULIC SYSTEM AND REMOTELY OPER- ATED FLOW CNTRL ARRANGEMENT THERElN John D. Allen, South Euclid, Ohio, assigner to lliawiclr Corporation, a corporation of Michigan Filed Feb. 18, 1965, Ser. No. 433,636 9 Claims. (Cl. 253-4) ABSTRACT F THE DISCLUSURE A flow control arrangement for selectively determining the speed of a hydraulic motor comprises a pressurecompensated flow regulator close to the motor, a rotary solenoid next to the tlow regulator, and a multi-'position selector switch remote from the tlow regulator and connected electrically to the rotary solenoid so that the rotational position of the output shaft of the rotary solenoid will correspond to the setting of the selector switch. This output shaft is coupled to a rotatable valve in the flow regulator which provides a variable orifice controlling the hydraulic tiow to the motor.

This invention relates to a hydraulic system and to a remotely operated hydraulic iiow control arrangement therein for regulating the flow to a hydraulic motor which is to be operated at a constant speed selectively determined bythe user.

Prior to the present invention, in systems of this general type it was necessary to provide a relatively complex and expensive hydraulic feedback circuit connected to the hydraulic motor to maintain its speed constant despite pressure changes in the supply tiuid or changes in the load on the hydraulic motor. In addition to their complexity and expense, such systems were not wellsuited for remote control operation, such as on highway maintenance trucks where the hydraulic motor drives a salt spreader and the driver of the truck should be able to selectively set the speed of the spreader from his normal driving7 position in the cab.

The present invention is directed to a novel and improved hydraulic system which is adapted to be remotely controlled and to a novel and improved hydraulic iiow control arrangement for use in such a system.

lt is an object of this invention to provide a novel and improved flow control arrangement for selectively regulating the speed of a hydraulic motor from a remote point.

It is also an object of this invention to provide a novel and improved hydraulic system embodying such a flow control arrangement.

Another object of this invention is to provide such a system which does not require a hydraulic feedback circuit associated with the hydraulic motor.

Another object of this invention is to provide such a system which does not require long hose connections from the remote control point to the hydraulic motor.

Another object of this invention is to provide such a novel and improved remotely operated tiow control arrangement which minimizes the liuid Ipressure losses in the supply system for the hydraulic motor whose speed it controls.

Further objects and advantages of this invention will be apparent from the following detailed description of a presently-preferred embodiment thereof, which is illustrated in the accompanying drawing.

In the drawing:

FIGURE 1 shows schematically a hydraulic system in accordance with the present invention, including the present tiow control arrangement connected for remote titl 3,381,935 Patented May 7, 1968 operation to control selectively the speed of the hydraulic motor in the system; and 4 FIGURE 2 is a fragmentary cross-section, taken along the line 2-2 in FIG. 1, through a portion of the ow divider in the present iiow control arrangement.

Referring to the drawing, the system shown therein comprises a hydraulic motor 1i), which may be of any suitable type, having an inlet 11 for hydraulic fluid under pressure and an outlet 12 for returning the hydraulic iiuid to a reservoir 13. Hydraulic tluid under pressure is supplied to the inlet 11 of motor 10 by a pump 1d, which pumps iiuid from the reservoir 13, through a control valve 15 and thence through a low regulator in the form of a pressure-compensated, priority-type ow divider 16, to be described in detail hereinafter. The control valve 15 controls both the supply lilow from the pump 14 to the flow divider 16 and the return iiow from the outlet 12 ofthe fluid motor 1t) to the reservoir 13.

in the particular embodiment illustrated, the ilow divider 1d comprises a cast housing or body 17 having an inlet port 18, a controlled priority iiow outlet port 19 connected to the inlet 11 of iluid motor 1t), an excess tlow outlet port 20.

The flow divider body 17 has a first longitudinal bore 21 which slidably receives a iirst valve member Z2. Valve member 22 has a Erst cylindrical land 23 which normally sealingly engages the bore 21 between an inlet passage 2d, connected to the inlet port 18, and a first outlet passage 25, connected to the excess flow outlet port 2t).

Valve member 22 has a second cylindrical land 26 which sealingly engages the first bore 21 between the rst outlet passage 25 and an intermediate annular groove 27 surrounding bore 21.

Valve member 22 has an additional, generally cylindrical, third land 28 which sealingly engages the lirst bore 21 to the right of groove 27 in FIG. 1. Between its lands 26 and 28 valve member 22 has a reduced diameter portion 29 which is spaced inwardly from the wall of bore 21.

Valve member 22 has an axial recess or passage 30 which is open at its right end and which communicates with bore 2.1 through radial passages 31 in its reduced diameter 4portion 29.

To the right of the land portion 23 on valve member 22 in FIG. l, the flow divider housing has an annular groove 32 surrounding bore 21 and communicating with the controlled priority iiow outlet port 1g.

A plug titl is threadedly mounted in the right end of bore 21 in FIG. 1. A coil spring 41 is engaged under compression between the inner end of this plug and the closed end of the axial recess 3d in valve member 22 to bias the latter to the position shown in FIG. 1, where the valve 1 and 23 blocks the inlet port 18 from the excess tiow outlet port 2li.

At its left end in FIG. 1, valve member 22 has a cylindrical pilot or guide oprtion 3d, which slidably engages the first bore 21 to the lett of the inlet passage 2d. This pilot or guide portion 38 is formed with an orifice 39 for equalizing the fluid pressure on its opposite sides.

The flow divider lbody 17 has a :second longitudinal bore 42 extending parallel to the iirst bore 21. At its left end in FIG. 1 this second bore 42 is open to the inlet passage 24. A cross passage 43 connects the second bore d2 to the first bore 21 at the intermediate annular groove 2'7 in the latter.

A control valve i-i is rotatably mounted in the second bore 42 to control the priority flow therethrough from inlet port 1t; to outlet port 19. This control valve has a cylindrical front end li5 which sealingly engages bore 42 just ahead of the cross passage 43. At this end the control valve has an axial passage 46 whose front end receives an orifice plate 47 with an orifice 17a therein. The orifice plate is held in place by a snap ring d8.

Communicating with the passage 46 behind the orifice plate 47 are a plurality of transverse passages 50, 51, 52 and 53 (FIG. 2) in the cylindrical front end 45 of the control valve 44 which together provide a variable orifice adapted to register selectively with the cross passage d3, depending upon the rotational position of the control valve 4d. As the control valve 44. is turned progressively in one direction the iiow through its variable orifice Sii-53 to the cross passage t3 increases from zero progressively to a maximum iiow rate, and then back to zero when the original rotational position of the control valve is again reached.

In the operation of this flow divider, there is a controlled priority iiow from inlet port 1S through the second bore 42, orifice 47a, passage 46 in control valve 4t", through the variable orifice Sil-53 in the latter, through the cross passage 43 in the How divider housing 17 into the annular intermediate groove 27 therein, through the radial openings 31 in valve member 22 into the axial recess 30 therein, and from the right end of that recess in FIG. 1 to the controlled priority liow outlet port 19.

The volume per minute of this fluid flow to the controlled priority flow outlet port 19 remains substantially constant despite fluctuations in the fluid pressure at the inlet port 1S or varying loads on either the hydraulic motor in the controlled priority iiow circuit or in the excess flow circuit. The controlled tiow rate may be selectively adjusted by turning the control valve 44 to determine the registration of the latters variable orifice Stb-53 with the cross passage 43 between the bores l2 and 21 in the iiow divider body.

In the operation of this flow divider, fluid delivered to the inlet passage 18 flows through the passage 42, oritice 47a, the variable oriiice StB-53 in valve member d4, passage 43, openings 31 in the valve 22, bore 30 in valve 22 to controlled ow outlet 19. When the input iiow exceeds the controlled iiow set by the variable orice in valve member 44, valve 22 moves to the right in FIG. l against the biasing force exerted by spring 41, rst opening to bypass fluid from the inlet port 18 to the excess flow outlet port 20. Should there be a tendency for continued increase in controlled flow after the valve 22 has opened the passage to bypass iiuid from the inlet port 18 to the excess iiow outlet port 20, the valve 22 will move further against spring 41 to restrict flow to the controlled ow outlet port 19 by restricting the passage between recess and the controlled flow outlet port 19. Valve 22 thus operates to maintain a fixed pressure drop across control orifices 47a and 50453 by either bypassing inlet iiow to the excess flow outlet port or by restricting the passage for inlet flow to the controlled flow outlet port to maintain a substantially xed iiow to the controlled iiow outlet port regardless of variations of pressure at either the controlled iiow outlet port 19 or the excess ow outlet port 20.

In accordance with the present invention the controlled priority flow to the iiuid motor 10 is set selectively from a location remote from the iiow divider itself. (In order to minimize hydraulic losses, the flow divider 16, the pump 14 and the hydraulic motor 10 preferably are as close as possible physically to one another, so as to minimize the length of the hose connections between them.) The rotatable control valve 4d in the iiow divider, whose rotational position determines the controlled priority ow Irate, has an integral stem which is coupled to the output shaft 56 of a rotary solenoid 57. The control valve stem 5S extends rotatably through a coupling plug 58, which has a screw-threaded inner end 59 threadedly mounted in the right end of the second bore 42 in the flow divider housing. A cover 60 for the rotary solenoid 57 carries an end plate 61 which snugly receives the coupling plug 58. A jam nut 62 is threadedly mounted on the screw-threaded outer end 63 of the coupling7 plug just inside the end plate 61.

The output shaft 56 of the rotary solenoid 57 is coupled to the stem 55 of the control valve 44 through a coupling 64, which imparts the rotational or turning movement of the solenoid output shaft 56 to the control valve 44, but permits a certain amount of axial movement of the solenoid output shaft 56 with respect to control valve 44.

The rotary solenoid S7 may be of known construction and mode of operation, the details of which are not part of the present invention. For example, it may correspond substantially to a rotary solenoid as disclosed in U.S. Patent 2,496,880 or 2,501,950. The rotary solenoid has an armature which is rotatable in step-by-step fashion in response to the closing of an external switch, this armature being coupled to the output shaft 56 so that the latter turns the same amount as the armature and is displaced a slight distance axially in response to the movement of the armature.

The rotary solenoid 57 is under the control of a remotely located, rotatable, selector switch 70 having a manually rotatable contact 71 which may be turned to engage any one of several circumferentially spaced fixed contacts '72, here shown as twelve in number. The several contacts of this selector switch are interconnected with the rotary solenoid 57 in a known manner such that the output shaft S5 of the latter will have a rotational position corresponding to that of the manually rotatable contact 71 of the remote selector switch 70. For example, if the switch contact 71 is turned from the zero to the 2 position, the rotary solenoid will be energized to turn its output shaft 56 to the same rotational position. Consequently, the control valve 44 in the flow divider 16 will also be turned to the rotational or angular position which corresponds to the rotational position of the manually rotatable Contact 71 of the remote switch 70. Thus, by turning this switch contact to the desired position, the flow divider can be adjusted to provide any one of several tiow rates to the fluid motor 10, the number of such different flow rates (including zero iiow rate) corresponding to the number of fixed contacts 72 in the selector switch.

With this arrangement, the rotary selector switch 70 may be mounted close to the operator of the system, such as in the cab of a truck, while the flow divider 15 and the rotary solenoid 57 are as close as desired to the fluid motor 10, so as to minimize the hydraulic losses in the system. For any particular rotational setting of the control valve 44- in the iiow divider, the controlled priority iiow to the fluid motor lil will remain constant despite changes in the load on this motor, or in the load at the excess iiow circuit, or in the inlet pressure to the flow divider. Accordingly, the speed of the motor 10 can be set selectively from la remote location and yet there is no necessity for complicated and expensive hydraulic feedback circuits for regulating the motor speed.

While a hydraulic system including a particular presently-preferred embodiment of the present liow control arrangement has been shown and described, it is to be understood that the invention is susceptible of other physical embodiments differing from the particular arrange ment disclosed and that various modifications, omissions and refinements which depart from the disclosed embodiment may be adopted without departing from the spirit and scope of this invention. For example, the flow divider 16 may be replaced by another type of :liow regulator, such as by plugging the excess iiow outlet port 20 in housing 17, in which case this valve arrangement will still function to regulate the flow to the controlled flow outlet port 19 in accordance with the rotational position of control valve 44 independent of the iiuid pressure at either port 18 or port 19. In such case, member 22 would function as a pressure-compensating piston which is adapted to restrict the flow to outlet port 19 and thereby maintain a fixed pressure differential between ports 18 and 19 as determined by the setting of control valve dfi. Also, if desired, the step-by-step rotary solenoid 57 may be replaced by any other type of rotary actuator having an output shaft whose rotational position will be determined by a remotely located variable electrical control device, preferably manually operated.

I claim:

1. A iiow control arrangement comprising:

a variable electrical control having a plurality of different stable operating positions to which it may be set selectively;

an electrically operated rotary actuator having a rotatable output shaft and connected electrically to said control to have the rotational position of said output shaft determined by the setting o-f said control in each of said operating positions of said control;

and a flow regulator having an inlet port and a controlled flow outlet port, a rotatable control valve between said inlet port and said controlled iiow outlet port and coupled to Said output shaft of the rotary actuator to be turned by the latter and operative to control the flow between said inlet port and said controlled flow outlet port in accordance with its rotational setting, and means operable to hold substantially constant the flow to said controlled ilow outlet port, for a given rotational setting of said control valve, independent of the uid pressure at said inlet port or at said outlet port.

2. A flow control arrangement comprising:

a variable electrical control having a plurality, greater than three, of different stable operating positions to which it may be set selectively;

an electrically operated rotary actuator positioned remote from said control and having a rotatable output shaft, said rotary actuator being connected electrically to said control such that the rotational position of said output shaft corresponds to the setting of lsaid control in each of said operating positions of said control;

and a fiow regulator positioned close to said rotary actuator and having an inlet port and a controlled flow outlet port, a rotatable control valve disposed between said inlet port and said controlled ilow outlet port to control the fluid flow between them, said control valve being coupled to said output shaft of the rotary actuator to -be turned by the latter', said control valve having variable orifice means thereon which controls the ilow rate between said inlet port and said controlled flow outlet port in accordance with its rotational setting, and pressure-compensating means connected between said inlet port and said outlet port and operable to maintain substantially constant the fluid pressure differential between said inlet and outlet ports so as to hold substantially constant the flow to said controlled iiow outlet port, for a given rotational setting of said control valve.

3. A ilow control arrangement according to claim 2,

wherein said rotatable control valve has means thereon defining a `fixed fiow restriction orice between said inlet port and said variable orifice means.

4, In a hydraulic system, the combination of:

a source of hydraulic liquid under pressure;

a hydraulic motor;

and a flow control arrangement for selectively reguhating the speed of said motor comprising a variable electrical control positioned remote from said motor and having =a plurality of different stable operating positions to which it may be set selectively;

an electrically operated rotary actuator having a rotatable output shaft and connected electrically to said control and operative to position said output shaft at a rotational position which corresponds to the setting of said control in each of said operating positions of said control;

and a flow regulator positioned close to said motor and having an inlet port connected to receive hydraulic liquid from said source and a controlled flow outlet port connected to the inlet of said motor, a rotatable control valve between said inlet port and said controlled flow outlet port and coupled to said output shaft of the rotary actuator to be turned by the latter and operative to control the tlow between said inlet port and said controlled flow outlet port in accordance with its rotational setting, and pressure compensating means connected between said inlet and outlet ports for regulating the flow through said control valve to said controlled fiow outlet port so as to maintain said iiow substantially constant for a given rotational setting of said control valve.

5. A hydraulic system comprising:

a hydraulic motor;

a pump for operating said motor;

and a iiow control arrangement for selectively regulating the speed of said motor comprising a variable electrical control positioned remote from said motor and having a plurality of operating pio-sitions to which it may be set selectively;

a rotary actuator having a rotatable output shaft and connected electrically to said control to have the rotational position of said output shaft determined by the setting of said control in each of said operating positions of said control;

and a ilow regulator positioned close to said motor and having an inlet port connected to receive hydraulic liquid from said pump and a controlled flow outlet port connected to the inlet of said motor, a rotatable control valve disposed between said inlet port and lsaid controlled flow outlet port to control the uid flow between them, said control valve being coupled to said output shaft of the rotary actuator to be turned by the latter, said control valve having variable orifice means thereon which controls the flow between said inlet port and said controlled flow outlet port in accordance with its rotational setting, and a pressure-compensating member connected between said inlet and outlet ports and slidable in response to the fluid pressure differential between said ports to variably restrict the ow to said outlet port so as to hold substantially constant the flow through said control valve to said controlled flow outlet port, for a given rotational setting of said control valve, independent of the fluid pressure at said inlet port or said outlet port.

6. A system according to claim 5, wherein said rotatable control valve carries means defining a fixed flow restriction orifice between said inlet port and said variable orifice means.

7. A flow control arrangement comprising:

a multi-position selector switch having a plurality of different stable operating positions to which it may be set selectively;

a rotary solenoid having a rotatable output shaft, said rotary solenoid being connected electrically to said selector switch and operative to position said output shaft at a rotational position corresponding to the setting of said selector switch in each of said operating positions of said switch;

and a flow divider positioned close to said rotary solenoid having an inlet port, a controlled priority flow outlet port, an excess flow outlet port, a rotatable control valve disposed between said inlet port and said controlled priority flow outlet port to control the fluid flow between them, said control valve being coupled to said output shaft of the rotary solenoid to be turned by the latter, said control valve having variable orifice means thereon which controls the flow between said inlet port and said controlled priority flow outlet port in accordance with its rotational setting, and pressure-compensating valve means connected between said inlet port `and both said outlet ports and operable to regulate the ow through said rotatable control valve to said controlled priority flow outlet port, for a given rotational setting of said control valve, by controlling the connection of said inlet port to said excess flow outlet port and Variably restricting the flow from said variable orice means to said controlled priority flow outlet port.

8. In a hydraulic system, the combination of:

a source of hydraulic liquid under pressure;

a hydraulic motor;

and a flow control arrangement for selectively regulating the speed of said motor comprising a multi-position selector switch positioned remote from said motor and having a plurality of operating positions to which it may be set selectively;

an electrically operated rotary actuator having a rotatable output shaft and connected electrically to said selector switch such that the rotational position of said output shaft corresponds to the setting of said selector switch;

vand a ow divider positioned close to said motor and having an inlet port connected to receive hydraulic liquid from said source, a controlled priority flow outlet port connected to the inlet of said motor, an excess flow outlet port, a rotatable control valve between said inlet port and said controlled priority ow outlet port and coupled to said output shaft of the rotary actuator to be turned by the latter and operative to control the flow between said inlet port and said controlled priority flow outlet port in accordance with its rotation-al setting, and pressurecompensating valve means subjected to the pressure differential between said inlet port and said controlled priority llow outlet port aud controlling the ow between said inlet port and said excess How outlet port to hold substantially constant the flow through said rotatable control valve to said controlled priority flow outlet port for a given rotational setting of said control valve.

9. A hydraulic system comprising:

a hydraulic motor;

a pump for operating said motor;

and a ow control arrangement for selectively regulating the speed of said motor comprising a multi-position selector switch positioned remote from said motor and having a plurality of operating positions to which it may be set selectively;

a rotary solenoid having a rotatable output shaft and connected electrically to said selector switch to have the rotational position of said output shaft correspond to the setting of said selector switch in each of said operating positions of said switch;

and a flow divider positioned close to said motor and having an inlet port connected to receive hydraulic liquid from said pump, a controlled priority flow outlet port connected to said inlet of said motor, an excess ow outlet port, a rotatable control valve disposed between said inlet port and said controlled priority flow outlet port to control the iiuid tlow between them, said control valve being7 coupled to said output shaft of the rotary solenoid to be turned by the latter, said control valve having variable orice moans thereon which controls the flow between said inlet port and said controlled priority flow outlet port in accordance with its rotational setting, and pressure-compensating valve means having a first Valving portion thereon which controls the fluid flow from said inlet port to said excess ow outlet port and having an additional valving portion thereon which variably restricts the ow between said variable orifrce means on the control valve and said controlled priority tlow outlet port, said pressurecompensating valve means being subjected to the fluid pressure differential between said inlet port and said controlled priority flow outlet port to have its position determined by said pressure differential whereby to hold substantially constant the flow to said controlled priority flow outlet port, for a given rotational setting of said control valve, by controlling the tluid connections between said inlet port and said excess flow outlet port and between Said inlet port and said controlled priority flow outlet port.

References Cited UNITED STATES PATENTS 2,402,280 6/1946 Green 251-131 X 2,789,576 4/1957 Mitchell 253-1 X 2,859,762 11/1958 Banker 137-116 X 3,125,110 3/1964 Allen et al. 137-101 3,137,475 6/1964 Schoenecker et al. 251-133 X FOREIGN `PATENTS 658,161 10/ 1951 Great Britain.

EVERETTE A. POWELL, JR., Prima/'y Examiner. MARTIN P. SCHWADRON, Examiner. 

